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Exos 2GT - PMC-8 Thread


Ben K
 

I ordered from High Point Scientific, and it indicates a 12V battery back, supplied by 8 D batteries.


Is there an AC adapter available for this? If not, aside from being 12V, what amperage is needed?


Ben K
 

Also, this is currently my understanding of how I'm going to wire everything up. 

I'll replace the DSLR with an astronomical camera in time, and may add dew heaters in time, depends on what I upgrade my OTA to, in time.



W. Christopher Moses
 

My PMC-8, which came with the G-11, included a power supply. I would be surprised if your does not.  It is a standard 12v power supply. I don't remember the amps, but it isn't very high.  Nothing you couldn't buy at K-Mart


W. Christopher Moses
 

Hi,
  If you already have AC power, I wouldn't bother using batteries for the pmc-8.  It just seems like another possible point of failure to me, personally.



Ben K
 

Agreed, I would far rather just use AC, the high point site indicates it comes with a battery input. I think it's old, from the old exos 2gt, not the PMC 8 version, but my mount doesn't arrive till Wednesday. I'll take some pics then, of the unboxing, and modify the flow chart as needed.


W. Christopher Moses
 

A PMC-8 is a PMC-8, as far as I know.  I think you are correct that it was just old copy. My PMC-8 came with the power supply in the same box.


hubbell_jerry@...
 

Sorry for my delayed response, the EXOS2 version of the PMC-Eight comes with a battery pack, not the AC adapter as the G11. We are practically giving the mount away with the controller, so we have to save a few dollars somewhere! Anyway, like was said previously, you would want to use a larger battery system anyway. If you have an automotive jump battery, that would work fine. If you want to buy an AC adapter, a 12 Vdc, 3 amp supply should provide good service. A 5 amp version would be more than adequate.


Ben K
 

Jerry, do you have a specification for the plug end for the PMC-8?

Chris, what is your adapter, 12V 3A?


hubbell_jerry@...
 

Hi Ben,

Here is the digikey part for the connector you need. It is a 2.1x5.5 mm plug

The connector on the PMC-Eight is this one:

This is the standard jack and plug used on Meade and Celestron telescope mounts

 


hubbell_jerry@...
 

Hi Ben,

I was looking at your setup diagram and noticed the USB to DB9 serial adapter. The cable you have linked has a Prolific chipset. I have found that the FTDI chipset is more reliable and is the recommended chipset for use with the PMC-Eight. Chris and others may be able to speak more to the use of Prolific or other chipset USB adapters. The Prolific chipset may work fine and I am recommending the FTDI FT232 chipset because I know they work, that's all.


W. Christopher Moses
 

It is 12V, I think 3A. Everything else runs off a 10A supply, but I'll probably move the PMC-8 over to the 10A supply just to eliminate the cable.

You can get a good idea of my wiring here:


I just posted some pictures of the above the mount set-up


W. Christopher Moses
 

I've used both with the PMC-8 without problem, but I don't trust the Prolific.  I've seen to many problems with them on other astro setups, including my own.


Ben K
 

Much obliged to you both for catching that.

I've replaced it with an FTDI chipset cord.


Ben K
 

Jerry / Chris,

Do you know if the PMC expects positive tip/negative sleeve or negative tip/positive sleeve.

Or, can you upload a photo of the label on the adapter?

Currently looking at this, provided the polarity is right:



W. Christopher Moses
 

Hi,
I assume the tip is negative and the sleeve is positive. That is the convention, if I recall properly. Actually I spend a good amount of time today splicing wires, but at 5am my brain is getting foggy. I'll double check tomorrow if you want but I doubt they are doing anything unconventional. Of course, I've said similar things before...


hubbell_jerry@...
 

Hi Chris,

You are NOT correct about the power connector. The outside barrel is NEGATIVE and the Tip is POSITIVE. There is reverse polarity protection on the board so if you were to wire it backwards nothing would light up.


W. Christopher Moses
 

Yeah, I knew I shouldn't have answered that at 4 am.


Ben K
 

Turns out the pmc-8 just ships with an AC adapter and that's that.


Ben K
 

@Jerry or @Chris

I've connected my PMC-8 to my exos II. I connected my computer to the wifi of the PMC-8, and when I open Explorestars, I get "Data Files Missing" and the PMC-8 box starts making a manual, on-and-off-again hissing sound, like a very slow platter hard drive access sound.

Any ideas?


Ben K
 

Alright, I got the app working, Scott and Greg say in their video to put the 3 files and 1 folder in the pictures folder. What they mean to say is to put the ExploreStars folder, with 3 files and 1 subfolder, into the pictures folder. :D

Testing to see if the hissing is still there...